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Postby aquadeep » Mon May 18, 2009 9:30 am

Yes please see the website:http://www.eagletreesystems.com/OSD/OSD.htm

You must mean no wires from bellow the water,no it won't do that ,a tether and bouy with TX unit to shore tranmition would have to be employed great for ROVs.

It simply overlays the info on the existing camarra set up.

There is somthing I am working on that does not use the usual frequencies yet is legal, but its sensored right now about the wireless video underwater issue,I hope it works!

If you could get those tiny digital compases to interface with this system it would be breat even if the read out is on the dashboard ,since GPS prabably won't penetrate very far down.

Wait I have a GPS unit Garmin Ill stick it in a test vessel and see if it can detect the satalites and how far down,it has a log capability ,will post results soon. 8)

This is getting very excieting indeed :D :D
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Postby Andreas_dk » Mon May 18, 2009 11:03 am

Hi Aquadeep

Well I guessed so, if that system could transmit video live without a boy, then everyone would use it in their subs.

It would certainly be possible to produce a compass sensor, thou my local electronics suplier does not have any compass chips. Digikey.com has some, so connecting one of those with a microcontroler, controling a Digital to analog converter (and then using an analog module from Eagle Tree) or I guess you could use the rpm sensor (making a fake output ranging from 0 - 360 rpm). A fake temperature sensor output would be possible too I guess, though everything exept for the analog sensor requires some study of the sensors first. (I use my osciloscope for that, but most people don't have an osciloscope).

This process is indeed thrilling. Just ask me for help on the home made sensors, (I have done some electronics including microcontrolers).

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Postby aquadeep » Mon May 18, 2009 3:51 pm

Great now where talking ,the eagle Tree system has two analog input ports already for setting up home made sensors.

Also more temp sensor capability would be nice.

The altimiter sensor is the Im useing for Depth and it is very sensative and thats great but it would be better if the readout could be in cm or fractions of an inch then to feet ect scaled out to what ever the sensor can handle ,Rc subs generaly don't need to go to deep but an accurate sensing range would be sweet indeed,its almost there already as the depth reads out very well just not in common units ,it seems to be in the cm increments though.

I bet even a sonar interface could be made also as done on Robots just useing the marine sensor,great for obstacle avoidance ect.

Yes Digikey and a few others have interesting miniature compasses and inclinometers,the Pro vertion system even has a variomiter that sounds off the rate of decline or rise!MMM
Also its 1watt of power TX is very interesting but man that one is pricy.

another important sensor would be a knot meter,iether by sonar that would be better or mechanical means.

Dave :D
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Postby Andreas_dk » Tue May 19, 2009 1:49 pm

I couldn't resist do a little calculations on the altimeter used as depth sensor.

Now thinking of pressure as the mass ( including air and water if any ) above you, a change of 1 foot in height (in air) yealds a pressure change of 0,00004 bar.
Now one foot in water gives a pressure change of: 0,03 Bar, so when the sensor is 1 foot below water level it feels a pressure 0,03 bar larger than its altitude 0. As a result the altiometer will dsiplay a negative value about 784 times too large.
Eks:
The altiometer shows -10 feet:
-10/784 = -0,01275 feet. The sub is 0,0127 feet below surface, not 10 feet. So dividing the readout with approximately 1000 is rather close.

or as a thumb rule: 1000 feet is actually about 4 meters.

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Postby aquadeep » Tue May 19, 2009 7:11 pm

Thats very interesting and I think we are well on our way to getting a depth sensor taylord made for the Rc Sub! :D :D :D

A large sellection of microw pressure sensors are available and should be just a matter of sellecting the right one,some trail and error I'm sure but a less sensative or waighted (I am not sure of the technical term)sensor is needed.

The nice thing about the EagleTree sytem is that it utilizes standard microw controller and sensory protocals that can be used on a huge range of sensor types and even anolog to digital interface capabitities which is VERY important for development proto baords ect.

I have faith in you and Yes its coming to us all. :D
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Postby Ramius-II » Wed May 20, 2009 9:25 am

Hi All!
This is a few posts late and for the digital compass http://www.robsonco.com/Dinsmore/Untitled_5.html will point you to the explaination, a drawing, and the PIC programming for a hall effect compass. Independent tests showed the compass is accurate to 1/10 of one degree as the software has a built-in self calibrating routine, that is each time you do a full 360 degree turn the compass is re-calibrated for changes in voltage, etc. Hope this is of some value.

Depth should not be much of a problem as you can reverse the static and pressure tubes. The main catch I found was that one additional parameter is desireable for accuracy and that is to set and reset the reference pressure to compensate for changes in barometeric pressure.

Best, Ed
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Postby aquadeep » Wed May 20, 2009 3:57 pm

Those work well I have one I made with LED indicators,they are durrable and cheap in kit form.

Ther are some very compact non halleffect digital compasses that are used in robots and have very high accuracy but can cost a lot more.

I am developing a simple solution to recieving live directional updates as the sub is under the water,as I don't think GPS will be able to penetrate all but a few inches if that in pond water.

Ill be testing it soon and will post the findings,it will work independantly from the Eagle Tree Systems telemetry ,it will do several other things that the telemetry sytem wont be able to do and will work at much deeper depth.

Stay tuned its looks good! :D
"I like submarine comanders ,they don't have time for bull!!" and
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Postby Myles Yancey » Wed May 20, 2009 7:13 pm

Hello again everyone just a word of advise concerning the Egle Tree telemetry system.

Today I call the company, and was going to purchase one of these systems, but before I did so I spoke with the lead tech. at the company.

he advise me that at this time and date the system had no practicall uses in the RC Model Submarines Hobby, also that they had no real experences with Rc Submarines.

Quote from Aquadeep
"You want depth ya thats right depth is posible since the sensors use barometric pressure and with some tweaking It is posible to get a read out live of the depth she is running at thugh not calibrated to meters or feet but a live representation of change in depth numericly,later I might be able to get the manufacturer to make the option in a depth gage ect read out.
Even the internal pressure of the Casing can be detected !Ballast tank and pump pressures measured.Even speed is an option."

The company has informed that the above quote is not possible with out a special sensor and with out parcially reprograming part of the systems programing.

The company also stated that the only way the system can be recalibrated and programed is through them at a non refundable Engineering fee. there is no acess to the programing in the system.

The Company also gave a contact point tothe actual developer of the system and I sent him mail with my concerns and question which I will post on the board when I hear back from him.

So with all due respect to Aquadeep I advise everyone to look deeply before you start spending your had earned money on something he is telling you, there are less expensive tools out there that will give you the same results such as speed, RPM's and temperature.

Thank you again

Myles[/url][/u]
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Postby aquadeep » Sat May 23, 2009 12:23 am

Here is a quick video clip of the first run of the telimitry system I made durring a nasty storm it was cut shurt because the lights wen't out .This is about at the end of the test that lasted 45 minutes.

The sreen says MTA that means Motor Temp A sensor and reads 96 and that is in farenhight.

The Subs radio recievers voltage is displayed bellow that and can be seen fluctuating giving exact readings under live submerged conditions at depth of about 3 ft .

The other reading Skip "speed" that one is not hooked up to nothing it uses barometric pressure and if you where to look at the pdf document from the maker it shows how speed is meassured with an aircrafts pitot tube.
Not speed of the props that is read as RPM and is on the next screen.

As I mentioned before the speed of the sub has to be measured with a different type of sensor called a knot meter and then made so that the system can interprit the sensors output in knots or miles per hour,after all the sub IS in a test tank and won't go very fast or far,right?
The sensor is reading the pressure inside of the casing,I know you did not know that about the sensor and I am not crtisizing you for that.

Why show speed of the vessel in this test ?What is important in this test is the motor temp on sensor A ,after about 45 minutes the temp went up to 96 degees,there it stayed till I ended the test as seen in the graf since I want to run again with the cooling system turned off with equal time.To save batery power for that test.

The water is cooler than at the lake ,on the very first post,the temp went mutch higher to 118f.

Colder the water better the cooling effect.

Water is moving around the sub because the prop is turning at around 270 rpm and it is hard to see ,next time Ill make sure its more visable also if it was not running forward why is the sub up against the end of the tank with that kind of current flowing around it,it should have moved bachwrds or to the sides in the tank?

I run very cool motors geared very well and matched to the sub.


I could not show the other screen that shows the RPM because I was by myself and holding the TX and the video camarra at the same time taking the clip as smoth as possible was difficult enough.I will show the RPM tomorrow in a reapeat of the same test but better video.

Tomorrow I will make much longer clips and show more grafs of the systems read out with the water cooling off I am sertain that the temp will go up.

Lets make somthing clear, I can nor do I know how or have the equipment to edit or doctor these videos and would not do it to make the findings in my favor ,I am not that kind of guy and as it has been expressed by a fella that I probably would do such a thing than thats his opinion,it would be neat to actualy make MOVIE MAGICK.

http://www.youtube.com/watch?v=yNtpviaVKWw

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The gray scale line is temp sensor A ,the prop RPM is a bit screwy in its read out but Ill have to see why its reading that way.
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Postby Andreas_dk » Sat May 23, 2009 10:24 am

Hi again.

I have seen, that Eagle Tree sells a pivot for boats.
One thing you should make sure, when attaching the pivot is, to keap it away from the sides of your hull, because the water close to the hull is accelerated as a result of the resistance between hull and water. Now I don't know how thin this stream of water along the sub is (my guess is somewhere between 1mm and 50mm), but I guess it would yeald accurate readings placed in the sail (in top) or in the nose of the sub.

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Postby Ramius-II » Sat May 23, 2009 12:19 pm

Hi All!
While I would never say that a pitot tube would not work, if you look at how they are installed on an aircraft they are mounted on the leading edge of the wing or away from the body of the aircraft. I truly believe this is the wrong type of sensor for our use. I would also wonder if the small holes in the outer tube of the pitot tube would allow water in and eventually destroy the pressure sensor. I would also imagine that the best approach is to make a list of what information you wish and then proceed from there. Just a though.

Best, Ed
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Postby aquadeep » Sat May 23, 2009 1:16 pm

Yes Rameuse II that is why I used the altimiter sensor to show some kind of depth readout,later a knot meter and proper depth meter will be made by iether the maker or by someone that has that experise.

As was stated to me by the owner of the Eagle Tree Systems ,when there is more interest in the system apllied to RC Subs the soft ware and new specialized sensors will be made.

Af couse the maker would say that the system is not intendid for subs ,at least "not yet".That however does not mean that it can't or should not be tried to be apllied and find out what it can do,just the fact that it works under water is worth the small investment is a very easy to use and aplly to a RC Sub.

I did not modify in any way the systems electrinics or software,I don't know how.And would not have, if it did not work under water I might have returned it and thats why the folks at Eagle Tree are a great organization and great suport,there is no risk ,just allot of fun finding out what realy goes on in your sub.The Eagle Tree web site shows,boats are using the same sytem,aren't
subs "boats that dive". :wink:

I rest that point.


I will post more videos today that will be better in showing the Porp rotating beter and that the sub is in fact on the bottom and that the coling system is tuned off and on findings,please be patient its coming.

Dave :D
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"Don't tell me it can't be done!"

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Postby Ramius-II » Sat May 23, 2009 4:38 pm

Hi Dave!
For the most part you are correct and I agree. For some time now I have been developing sensors specifically for subs. Some of my approaches are a little different as I strive for the highest accuracy possible. My compass design is good to 1/10 of 1 degree as stated by a Chinese engineering company.

As for depth, again there are some factors to consider. The first factor is the "current barometeric pressure". The pressure sensor used has a vacuum on one side and a pressure sensor on the other side as all pressure sensors are a membrane that is flexed. The only way that I know of to maintain accuracy is to take a pressure measurement on the surface, store this reading and use it as your reference point. In aircraft for altitude, you always "set" your altimeter to what the tower tells you. To me, it is a simple process, use a "water detector" to determine when you are on the surface then set your "base point". Each time you surface, you would be basically re-calibrating the depth sensor and not having to reset the whole system. For mine, I am good to 1/2".

For speed, I got away from a pitot type sensor for many reasons, mainly that accruacy is difficult to maintain with all the variables. To be accurate, the pitot tube would have to be ahead or away from the sub because as water (or air) passes over a surface such as the hull, it will have a lesser pressure. If you look at test and experimental aircraft you probably have seen some with a long "pole" sticking out the nose of the plane which is the pitot tube. We do not , hopefully have to worry about ice forming so a standard non-heated flowmeter will work fine.

For motor RPM, I went with a standard disk that has black and clear strips. I have been shying away from magnets from not knowing at what point will all these magnetic affect the compass? The use of strips also has the advantage that the signal is either off or on whereas with magnets you will have a partially on or off as you start to get closer or away from the magnet.

Maybe I am too much of a prefectionist and in our appications it really does not matter? My main goal was no moving parts, small as possible, and everything is automatic and transparent to the end user. I think Eagletree has done a fine job and I would probably buy parts of their systems. I also think you are right that to know if there are limits is very useful. If I can help, please let me know.

Best, Ed
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Postby aquadeep » Sun May 24, 2009 12:04 am

Here is another clip I made today that shows a read out DEP ,notice how sensative its reading as the sub bairly moves verticly in the water colum.

The numbers are just an indication of movement at this time as a more exact read out in cms is being looked into, the Altimiter sensor is the one used for indicating and the name shanged on the dashboard to say DEP notice its in (-) numbers and incrases as the sub dives,decreases as the sub rises. Just like a depth meter :cool:
The sensor has a diaphram with a sealed chamber on the sensing inner side ,and I believe its auto resets to what ever the present barometric pressere is.
The other number on the right is the SIG or signal strenght at 90 plus and 100 is maximum and the sub is submerged about 2.5 feet,not bad at all this thing works! :)

The prop is moving as shown and the water is bieng moved around at strong cuurent as seen when a small flare comes up in the bigining,there is no daugt that it is moving. :rolleyes:

The way I made the antena now gets a lot beter strenght without being bulky and is super simple able to be permantly intalled so that the units TX can be removed and transferred to another sub without having to reasealed the casing sea diagram,this water has about 3 cups of clorine in it and still good signal even in a metal tank that could give problems.

If I had a third hand I could have shown the other sacreans that show motor temp and reciever voltage.

This video is very important as it shows how a wireless device can measure or display a subs depth ,and a hole host of very important data,its about time guys and I did it! :) :p

Alarms can be setup to warn you that depth is past max or prop RPM exceeded even temps of motors and ESC ectra ausume. :) http://www.youtube.com/watch?v=T61jb3l0JmQ

All this info and more like direction electrical peramiters can be displayed on a laptop without being on the TX,or overlayed on a clor view screen,but not while under the waves,but good for ROVs that have tethered video output.

Stay tuned as I post more ,this hobby is changeging now befor hour eyes. :P

Dave Amur Sub Yard :) :) :p
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